Many former cokes plants and gasworks sites are characterised by heavily
contaminated (PAH, TPH, creosote, cyanide, BTEX, etc) soils and groundwater
and are presently situated in economically interesting and valuable locations
(near city centres, close to roads and waterways). To determine the potential for
redevelopment of these brownfield sites, an evaluation tool was developed based
on three main steps: Risk, Remediation and Redevelopment (RRR). This
methodology was applied on the former Carcoke cokes plant located in the
Zeebrugge harbour area, Belgium. In a first step the human health risks posed by
the known contaminations were quantified for different protective scenarios for
each individual area of a grid superposed on the site. These scenarios went from
no protection measures to a removal and isolation of the contamination. In a
second step six potential redevelopment scenarios were evaluated based on their
minimum infrastructural needs and potential for human exposure. In a third step
the protection measures were converted in concrete remedial actions taking into
account feasibility and local legislation. For each remedial technique and each
area a cost was determined. The combination of the three steps (RRR) lead to a
matrix that was used to determine the optimal redevelopment scenario with a
minimal remedial cost and sufficient guarantee to prevent exposure. The
RRR-methodology reduced the remedial costs by over 30% compared to the
initial more traditional risk-based remedial plan. It also determined what areas
were not suitable for build-on activities (warehouse, offices) taking into account
\“reasonable” remedial costs to sufficiently reduce the exposure risk. The
methodology was also used to allow for temporary use of the site as an outdoor
storage facility taking into account the necessary protection measures.
Keywords: risk-based, remediation, redevelopment, cokes plant, gasworks, cost
reduction, land-use, soil contamination, human health, evaluation methodology.